Electrical conductor



' Sept. 23 1924. 1,509,102

A. s. DANA ELECTRICAL CONDUCTOR Filed Jan. 26 1920 ELI 67770 Dims/7E0[590 COVER/W6 mulflr/oly 5 -Zf6'77?/6 60/7500 77/76 W//?E INVENTOR m 4M43%;

A TTOHNEY Patented Sept. 23, 1924.

UNITED STATES PATENT OFFICE.

,ALAN STANDISH DANA, OF SEYMOUR, CONNECTICUT, ASSIGNOR TO THE KERITEINSULATED WIRE AND CABLE COMPANY, A CORPORATION OF CONNECTICUT.

n ELECTRICAL CONDUCTOR.

Application filed January 26, 1920. Serial No. 354,089.

To all whom it may concern.

Be it known that I, ALAN STANDISH DANA, citizen of the United States,and resident of Seymour, in the county of New Haven andState ofConnecticut, have invented certain new and useful Improvements inElectrical Conductors, of which the following is a specification.

My invention relates to electrical conductors and more particularly toelectrical conducting wires with protecting coverings. My invention isparticularly advantageous in the protection of insulated copper wires.

According to my invention I provide the electric conductor witha'coating or covering of a metal electro-deposited thereon,

' the physical characteristics of the metal coating being such that itremains coherent and substantially impervious under conditions of useand prevents any material diffusion of copper therethrough to theinsulation. For many years it hasbeen understood that copper and theusual rubber insulation should not be placed in intimatecontact and ithas been common to first cover the copper wire with tin. Tin has theadvantage that it requires only a moderate heat to melt it so that itmay be easily applied by dipping the copper wire into a molten bath ofit. Also tin alloys readily with copper so that at the temperature ofmolten tin a firmly adherent coating is obtained. For many years,therefore, the tin coating has been substantially the only coveringcommercially employed for the purposes in question.

Conductors of this class are likely to be subject to hard usage and toall sorts of atmospheric andv climatic conditions.v In some cases acidsor other chemicals are present either in liquid or gaseous form. Whilethe intermediate tin coating has heretofore been commonly employed, itis found that under some conditions, after a greater or less lapse oftime, the tin coating is destroyed, the inner surface of the insulationis deteriorated, the adhesion of the insulation to the conductor is lostand the surface of the copper is pitted. The immediate causes of this donot seem to be easily understood and therefore no remedy has beenpatent. It may be that the tin under certain conditions graduallybecomes wholly alloyed with the copper causing a disappearance of thetin layer and subjecting the insulation to the deteriorating action ofthe alloy.

Probably in some cases electrolysis between the tin, copper and theiralloys plays an important part. In some cases alternate wet and dryconditions seem to have something to do with it. The wide variation inthe thickness of tin coating as well as in the thickness of the alloymay possibly accelerate action by electrolysis. In any event, I havediscovered that by providing an adherent coating of a metal of certaincharacteristics,

these disadvantages may be largely if not entirely overcome. Also,according to my invention the coated conductor may be produced atrelatively low cost.

According to my invention in its preferred form the conductor issubstantially free of metal including alloy coatings which will form amaterial amount of alloy between the metal covering and the copperconducting wire, and which are materially more brittle than copper andwhich melt at a point near the melting point of copper, such would bethe case if a compoundof (for example) .equal quantities of copper andBabbitt metal were placed on the wire by running the wire through amolten bath thereof.

According to a preferred form of my invention I provide a copper wireconductor having a thin continuous covering of lead of uniform thicknesselectro-deposited thereon, the lead being coherent and adherent to thecopper and being substantially pure and of substantially the density andhomogeneity of cast lead, whereby it remains substantially imperviouswith the bending and use of the conductor, and with a rubber-compound orother insulating covering containing rubber surrounding the lead coveredwire adjacent thereto. The drawing is a perspective illustrating aportion of a conductor embodying my invention in one form. In thedrawing 1 represents the copper or other electrical conducting wire, 2the lead covering, and 3 the in- The thickness of the lead coatsulation.ing 2 isexaggerated on the drawing to more clearly illustrate the same.

In order that those skilled in the art ma more readily carry out myinvention, I wi 1 now describe my preferred method of makmatters,adhering to the wire.

' formed by reason of any sulphuric acid in potashin a suitable tank.This solution I makeby dissolving'3l2 grams of dry stick caustic in asuitable amount of water and then diluting the same with water to oneliter. If the tank be a large one several gallons of such a solution maybe used. The wire preferably passes down vertically into the solution,and around a pulley at the bottom and then passes u-p vertically. hereit comes outv of the solution I preferably pass it through a small glasstube to prevent dirt and the like on the surface of the solution frombeing drawn to and adhering to the wire as it isdrawn out of thesolution- An' electric current is passed through the caustic solutionfrom the wire as anode to the tank or other. suitable electrode ascathode. If necessary this bath maybe heated and agitated in anysuitable manner. By thus treating the copper wire it is cleanedthoroughly. However, any other suitable means may be used for cleaningthe wire, as pickling or sandblast. In some cases cleaningmay not benecessary.

From the caustic cleaning bath the sire is passed through a tank ofrunning water in order to remove any caustic and other A: similar glasstube may also be used at the exitof the wire from the water and ifdesired similar glass tubes may be used at the entrance of the wire inboth tanks.

From the tank of running water the wire passes through a lead fiuoborateelectrolytic bath in a suitable tank. In this bath the wire is made thecathode and a lead. plate the anode. Such a bath may be prepared bytaking 320 oz. of hydrofluoric acid and putting the same in a lead linedtank and slowly adding 140 oz. of boric acid. Afterthe solution hascooled,'190 oz. of basic lead carbonate are added with continuousstirring. The lead carbonate is added inthe form of a cream prepared bymixing it with a slight amount of water. The whole is then diluted to 10gallons and filtered through a paper filter to remove any lead sulphatethe hydrofluoric acid as an impurity. Before the electrolysis iscommenced 100 grams of liquid glue or gelatin are added and stirred in.The voltage will vary with the shape of and distancebetween electrodesbut is generally below one Volt and a current density of from to 260ampere-s per square foot is preferred.

The lead is deposited on the copper wire as it moves continuouslythrough the bath.

and I have found that not over 30 seconds is required between enteringof the wire and itsexit from the bath in order to deposit thereon asatisfactory lead coating. From the elect-ro-deposition bath the wirepasses through another tank of runnin water wherin the electrolyte iswashed.- ti'om the wire and it is then preferably passed through aheatedcylinder or subjected to a. blast of hot air to dry oil the water thatmay remain on the surface of the coated wire. The wire may then bereeled and later passed through any suitable type of apparatus whichpresses a rubber insulating compound of any suitable kind, around thewire to form an insulating coveringot uniform thickness. Or, from thedrying operation the wire may pass continuously through straighteningapparatus .of any suitable form and thence through polishing rolls andthen through the apparatus for putting on the insulating covering, afterwhich it is reeled. The wire may then be placed in to vulcanize therubber in a manner well understood by those skilled in the art.

The coating or covering of lead which is applied to the copper wire bythis preferred method is dense, coherent, continuous and adherent to thecopper and of substantially tight iron cylinders and subjected to heat 1uniform thickness and is substantially pure and of substantially thedensity and homogeneity of .cast lead and different from lead odswherein the lead is left more or less porous, flaky and non-adherent sothat it would coverings produced by various other methcoating adherentto the wire conductor. -By

the term wire I do not mean'to be limited to the ordinary wire I whichis circular in cross section since in the broader aspects of theinvention, the wire or. conductor may have any cross sectional shape-andmay be made up of a plurality of elements forming a conductor of anycross sectional shape.

VV-hile my improvements are particularly advantageous in connection withrubber insulated conductor for the reasons above given, nevertheless thelead coating has certain advantages as a'protecting coating for wireconductors where no such insulation is used. Also according to thebroader aspects of the invention the lead coating may beapplied in otherways so long. as it' is firmly adherent to the conducting wire and doesnot permit any substantial diffusion of the copper therethrough to therubber insulation, and does not form a brittle coating.

VVherever I use the term -lead in the. claims appended hereto, I donot'mean to limit the claim or claims to pure lead or substantiallypurelead except where it is so defined in the claim or claims, since asubstantial advantage is obtained even if the lead coating containssubstantial quantities of some othermetals or impurities.

: lVhat I claim as new-and desire to secure wire and adjacent to saidlead covering.

3. An electric conductor comprising a conducting wire having a coatingof lead electro-deposited thereon, the lead being coherent and adherentto the conducting wire, and an insulating covering surrounding the leadcovered wire.

4. An electric conductor comprising a copper wire having a thin coatingof lead elec trodeposited thereon, the coating being of substantiallyuniform thickness and coherent and impervious and an insulating coveringfor said coated wire.

5. An electric conductor comprising a copper Wire, having a protectivecoating of lead thereon firmly adherent to the copper,

and an insulating covering containing rubher outside of the lead coveredwire.

6. An electric conductor comprising a cop-- per conductlng wire having acovering of substantially pure lead around the same, and

an insulating covering containing rubber,

. ing rubber, outside of the lead covered wire,

the lead covering-on the wire being substan-' tially free of metalmelting at a point near the melting point of copper and which alloystherewith.

. 8. An electric conductor comprising a copper conducting wire, havinga: covering of lead around the same, and an insulating coveringcontaining rubber, outside of the lead covered wire, the covering onthe-Wire being substantially free of metal which is materially morebrittle than the copper of the conducting wire. Y 9. An electricconductor comprising a copper wire with flexible insulating materialsurrounding the same, the insulating material being of a nature to bedeteriorated if in contact with the copper, and a substantiallypure-lead covering between the wire and insulation and firmly adherentto the wire, the lead covering being substantially free of metal whichwould form a material amount of alloy with the wire' and cause materialdeterioration of the insulation.

10. An electric conductor comprising a metallic wire with flexibleinsulating material surrounding the same, the wire and insulatingmaterial being of a nature to react with one another if in contact withone another, and a' non-brittle lead covering between the wire and theinsulation preventing deterioration of the insulation by action from themetal of the wire.

11. An electric conductor comprising a copper wire with a flexibleinsulating material surounding the same, the insulating materialcontaining rubber, and a lead coating on the wire between the wire andthe insulation, and firmly adherent to the copper and substantiallypreventing reaction between the copper and the insulation.-

12. An electric conductor comprising a metallic wire with flexibleins'ulating material surrounding the same, the wire and insulatingmaterial being of a nature to react with one another if in contact withone another, and a coating of metallic lead electro deposited on the.wire underneath the insulation to prevent deterioration of theinsulation by action of the metal from the wire.

Signed at New York in the county .of New of January A. D. 1920. v y iALAN STANDISH DANA.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,509,102, 1924;, uponthe application of Alan Standish Dana,

Electrical Conductors,

an improvement in granted September 23, of Seymour, Connecticut, for

fication requiring correction as follows: Page3, line 28, claim 4, afterthe word wire and before the period insert the words Said insulatingcovering containing rubber; same page, line 36, claim 6', strike out thewords substantially pure and insert thesame before the word lead, line31, claim 5; and that the said Letters Patent should be read with thesecorrections therein that the Same may conform to the record of the casein the Patent Signed and sealed this 4th day of November, A. D. 1924.

' [SEALJ- KARL FENNING, Acting Commissioner of Patents.

' York and State of New York this 23rd day I errors appear in theprinted speci-

